Cancer patients have 'bigger risk of blood clots'

Cancer patients have a seven-fold increased risk of blood clots in their legs or lungs, scientists have announced.

Researchers in the Netherlands investigated 3,220 patients aged 18 to 70 with a deep vein thrombosis or a lung clot known as a pulmonary embolism.

They found that the risk of venous thrombosis was seven times higher on average in patients with cancer.

If a patient had a blood cancer, it raised the thrombosis risk 28-fold.

Those with lung cancer or gastrointestinal cancer were the next most likely to suffer blood clots.

The risk was highest in the first few months after the diagnosis of a cancer, the scientists found.

Patients with cancers that had spread to distant parts of the body were more at risk than those with more localised disease.

The researchers, led by Dr Jeanet Blom, from Leiden University Medical Centre in the Netherlands, wrote in the Journal of the American Medical Association: "It may be ... cost effective to consider prophylactic coagulant therapy for patients with cancer who have an increased risk to develop venous thrombosis."

The patients were compared with more than 2,000 healthy participants, who were the partners of study group members.

Both groups were questioned about risk factors for thrombosis. DNA samples were also taken to test for the gene mutations factor V Leiden and prothrombin 20210A, which both increase the risk of clots.

Carriers of factor V Leiden who also had cancer had a 12-fold higher risk of thrombosis than individuals with the mutation who did not have cancer.

Similar results were calculated for patients with the 20210A mutation.